from mpl_toolkits.basemap import Basemap
import numpy as np
import matplotlib.pyplot as plt

# read in topo data (on a regular lat/lon grid)
etopo = np.loadtxt('etopo20data.gz')
lons = np.loadtxt('etopo20lons.gz')
lats = np.loadtxt('etopo20lats.gz')
# create Basemap instance for Robinson projection.
m = Basemap(projection='robin', lon_0=0.5 * (lons[0] + lons[-1]))
# make filled contour plot.
x, y = m(*np.meshgrid(lons, lats))
cs = m.contourf(x, y, etopo, 30, cmap=plt.cm.jet)
# draw coastlines.
m.drawcoastlines()
# draw parallels and meridians.
m.drawparallels(np.arange(-60., 90., 30.), labels=[1, 0, 0, 0])
m.drawmeridians(np.arange(0., 360., 60.), labels=[0, 0, 0, 1], fontsize=12)
m.colorbar(location='bottom', pad='10%')
# add a title.
plt.title('Robinson Projection')
plt.show()
